The present invention addresses these disadvantages, and a general purpose thereof is to provide a disk drive device that reduces vibrations.
An embodiment of the present invention relates to a disk drive device. This disk drive device comprises: a hub on which a recording disk is to be mounted; a base rotatably supporting the hub through a bearing unit; a core fixed to the base, the core having a ring portion and a plurality of teeth that extend radially from the ring portion; coils wound around the plurality of teeth, the coils being three-phase driven; and a magnet fixed to the hub, the magnet being magnetized for driving with P (P is a natural number) poles along the circumferential direction and arranged to radially face the plurality of teeth. The hub has a convex portion of which the center is a rotational axis, and the convex portion is fit into the central hole of the recording disk. The rotational frequency N (Hz) of the hub satisfy N<F0/(3*P+2), where F0 (Hz) is an Eigen frequency of the second order rocking-mode resonance when not rotating in the situation where the recording disk is mounted on the hub.
Another embodiment of the present invention also is a disk drive device. This disk drive device comprises: a hub on which a recording disk is to be mounted; a base rotatably supporting the hub through a bearing unit; a core fixed to the base, the core having a ring portion and a plurality of teeth that extend radially from the ring portion; coils wound around the plurality of teeth, the coils being three-phase driven; and a magnet fixed to the hub, the magnet being magnetized for driving with P (P is a natural number) poles along the circumferential direction and arranged to radially face the plurality of teeth. The hub has a convex portion of which the center is a rotational axis, and the convex portion is fit into the central hole of the recording disk. An Eigen frequency F0 satisfy F0>N*(3*P+2), where F0 (Hz) is an Eigen frequency of the second order rocking-mode resonance when not rotating in the situation where the recording disk is mounted on the hub, and N (Hz) is a rotational frequency of the hub.
Optional combinations of the aforementioned constituting elements, and implementations of the invention in the form of methods, apparatuses, or systems may also be practiced as additional modes of the present invention.